4 ms·

tar actually makes sense with a little mnemonic: tar xzf $file - xtract - ze (actually gzip but fake-accent "the" is more memorable) - file

• mehrdadn 8y ago
  The most confusing thing about it for me now (after I eventually decided to learn it and figured out what you mentioned) is the missing dash. Somehow it works both with and without, which makes no sense considering how *nix tools work. Why is it made to be like that?
  • jldugger 8y ago
    Because it comes from an era before POSIX, when tapes were prevalent and bytes were costly.
  • cyphar 8y ago
    > Why is it made to be like that? The history of tar is quite long, but the short version is that it was first released as part of 7th edition Unix. It was a successor to tp[1] which was introduced in 4th edition Unix, which was a successor to tap[2] which was released in 1st edition Unix. In 1st edition Unix (as far as I could tell from looking through the man pages), no command had '-abc'-style flag support at all (so tap's semantics made sense). I imagine that quite a few users did something like 'alias tap=tp' and 'alias tp=tar' when upgrading, and so CLI backwards compatibility was required. As a result, everyone learned to use tar that way and it stuck. [1]: http://man.cat-v.org/unix-6th/1/tp http://man.cat-v.org/unix-6th/1/tp [2]: http://man.cat-v.org/unix-1st/1/tap http://man.cat-v.org/unix-1st/1/tap
    • mehrdadn 8y ago
      Wow, thanks!
    • junke 8y ago
      And all of this because originally, the Imperial Roman had no punctuation.
    • lifthrasiir 8y ago
      The same history applies to ps [1] which was introduced in 3rd Edition Unix. [1] http://man.cat-v.org/unix-6th/1/ps http://man.cat-v.org/unix-6th/1/ps
      • cyphar 8y ago
        Though from what I've seen, most people I talk to use the POSIX forms (such as 'ps -ef') and aren't aware that there is a BSD form (such as 'ps aux'). I've always used the BSD form, even though I came to Linux much much later, but I guess which form you use comes from where you learned basic *nix commands. I guess the lack of '-' with tar is more apparent because POSIX didn't create a different syntax, and so most people omit the '-' for terseness -- while with ps it would require learning a different syntax.
        • lifthrasiir 8y ago
          > I've always used the BSD form, even though I came to Linux much much later, but I guess which form you use comes from where you learned basic *nix commands. I too use the BSD form but came from the Linux world. Probably it is just a matter of taste (a common answer to everything!). > I guess the lack of '-' with tar is more apparent because POSIX didn't create a different syntax, and so most people omit the '-' for terseness -- while with ps it would require learning a different syntax. I argue the ps situation is worse than tar exactly because of that reason. There are three different classes of options in ps, often with slightly different meanings and sometimes with two different long-form options only distinguished by their cases...
    • oblio 8y ago
      And the (funny?) thing is that now the whole world has to suffer, probably millions of developers, because at one point tar had an installed user base of about 500 people. Yay for backwards compatibility :) Make is another famous victim of this: > Why the tab in column 1? Yacc was new, Lex was brand new. I hadn't tried either, so I figured this would be a good excuse to learn. After getting myself snarled up with my first stab at Lex, I just did something simple with the pattern newline-tab. It worked, it stayed. And then a few weeks later I had a user population of about a dozen, most of them friends, and I didn't want to screw up my embedded base. The rest, sadly, is history.
      • teddyh 8y ago
        > now the whole world has to suffer Bad example, since tar still works with a dash: tar -ztvf foo.tar.gz > Make is another famous victim of this: Now that is a much better example.
  • oneeyedpigeon 8y ago
    Sometimes I dream of a nirvana in which: - all unix commands support both short and long options - option letters/names are, at least to a much greater extent than currently, common across different commands
• Baal 8y ago
  No need for the ‘z’ :)
  • majewsky 8y ago
    Yeah, tar is actually pretty simple these days. (At least GNU tar, don't know about other tars.) In 99.9% of cases you only need to know the following: tar caf $archive $file... to create tar xf $archive to extract "x" will automatically recognize the compression format, and "ca" will automatically infer the desired compression format from the extension in $archive, e.g. tar caf backup.tar.xz /home/user makes an xz-compressed tarball.
    • talkingtab 8y ago
      tar has trained us so well: "... tar is actually pretty simple these days"
    • dingaling 8y ago
      I still prefer to pipe through a compression program on principle. tar has no good reason to messing around with compression, per the Unix single-function philosophy.
      • TremendousJudge 8y ago
        to people who grew up with archive programs, "making all of this into a single file" and "compressing all of this" is the same thing; requiring two commands is counterintuitive
  • craigds 8y ago
    You need it if you're processing stdin (curl ...file.tgz | tar xz)
• deleted 8y ago
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